title: Molecular heterogeneity of ferredoxin:NADP+ oxidoreductase from the cyanobacterium Anabaena cylindrica.
abstract: The enzyme ferredoxin:NADP+ oxidoreductase (EC 1.18.1.2) from whole filaments of Anabaena cylindrica can be separated into four major fractions by chromatography on phosphocellulose; chromatography using ferredoxin-Sepharose 4B proved to be less satisfactory in separating the fractions. The purified fractions, designated 1, 2, 3 and 4, all showed diaphorase and ferredoxin-dependent cytochrome c reductase activity. The major fractions present were 2 and 3 which were each obtained in an electrophoretically homogeneous state (forms 2 and 3) and represented 30-37% and 30-42%, respectively, of the total enzyme activity. Each was a monomeric species with a molecular weight of approx. 33 000 as determined by gel filtration and sodium dodecyl (SDS)-polyacrylamide gel electrophoresis. Evidence for the presence of a 70 000 molecular weight dimer was also obtained. Forms 2 and 3 had isoelectric points of 5.75 and 6.0, respectively, had similar kinetic properties and were flavoproteins. Extracts of isolated heterocysts showed no form 2 or 3 activity but contained a single form which closely resembled one of the species present in fraction 4; fraction 1 may have been a purification artifact because it was not detected in crude extracts of the cyanobacterium.
mesh_terms: D000458:Cyanobacteria / Q000201:enzymology*; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005287:Ferredoxin-NADP Reductase / Q000302:isolation & purification* / Q000378:metabolism; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification*
chemical_list: D007527:Isoenzymes; D005287:Ferredoxin-NADP Reductase; D009247:NADH, NADPH Oxidoreductases; D008058:Dihydrolipoamide Dehydrogenase